Glass which has low light reflectance and is transparent has been widely utilized in diverse fields such as various displays including smart devices, mirrors or glasses for vehicles, inner or outer glasses of buildings or home appliances, and the like. There have been attempted a number of researches to provide on the surface of a glass various functionalities such as fingerprint resistance or hydrophobicity plausibly sliding water droplets on the surface, and the like.
In order to grant hydrophobicity or water-repellency or reduce light reflectance on the surface of a glass, a method for forming a new surface structure has been attempted, in which the surface of the glass is etched or coated. However, since the glass is made of various materials, it tends not to be easy to etch the glass merely by applying general etching conditions. An attempt has been made to etch the glass surface using a toxic solution such as hydrofluoric acid (HF), but regardless of utilizing a technology using such toxic material it has been found that a particular nano-sized pattern is not formed on the glass surface in a feasible manner.
To fabricate a glass surface with high hydrophobicity and low reflectance, representatively applicable techniques include a method of uniformly dispersing particles on a glass surface to serve as a mask and executing plasma etching thereon, a method of forming a nano-structure by adhering particles on a glass surface via spraying, and so forth.
The etching process executed after coating the mask on the glass surface has advantages not only in excellent durability in that the nano-structure is directly formed on the glass surface per se, but in controllability of the nanopillar size by means of modulating etching conditions. However, since it is not easy to uniformly disperse the particles on the glass surface and is cumbersome to remove particle remnants after the etching, entire process steps are increased, and a process is necessary to utilize the toxic material for removing the particles remaining on the surface [Joonsik Park, Hyuneui Lim, Wandoo Kim, Jong Soo Ko, Journal of Colloid and Interface Science, 360, 272 (2011)].
As another process, there is a method of forming a structure by spraying particles with a particular size. The process is carried out in a manner of spraying and adhering particles of a material, such as TiO2 or SiO2, on glass using a chemical method or a sol-gel method to structuralize the glass surface using a nano-structure derived from the shape of the particle per se.
These methods have been known to be advantageous in that an etching process is not involved in a fabrication process because the particles are well-dispersed to form the structures on the glass surface, but to have a problem that adhesion between the particles and the glass surface is not easy.
That is, in the surface structure formed by the aforementioned method, the particles are apt to be readily separated from the glass surface in response to an external impact where the adhesive force between the particles and the glass surface is insufficient. In addition, the surface structure represents a drawback that cracks are easily generated between the particles [Taoye Wang, Tayirjan T Isimjan, Jianfeng Chen, Sohrab Rohani, Nanotechnology, 22, 265708 (2011)].